1. Field Of The Invention
This invention relates to valve systems of the type adapted to allow the introduction of a surgical instrument into a patient's body. In particular, the invention is applicable to a cannula assembly and the like wherein a cannula extends from a valve assembly and is intended for insertion into a patient's body and an instrument is inserted into the patient's body through the cannula.
2. Background Of The Prior Art
In laparoscopic procedures surgery is performed in the interior of the abdomen through a small incision; in endoscopic procedures surgery is performed in any hollow viscus of the body through narrow endoscopic tubes or cannula inserted through a small entrance incision in the skin. Laparoscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e. provisions must be made to ensure that gases do not enter or exit the body through the laparoscopic or endoscopic incision as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, laparoscopic and endoscopic procedures often require the surgeon to act on organs, tissues, and vessels far removed from the incision, thereby requiring that any instruments used in such procedures be relatively long and narrow.
For such procedures, the introduction of a tube into certain anatomical cavities such as the abdominal cavity is usually accomplished by use of a system comprised of a cannula assembly and a trocar. A cannula assembly is formed of a cannula attached to a valve assembly which is adapted to maintain a seal across the opening of the valve assembly. Since the cannula is in direct communication with the internal portion of the valve assembly, insertion of the cannula into an opening in the patient's body so as to reach the inner abdominal cavity should be adapted to maintain a fluid tight interface between the abdominal cavity and the outside atmosphere.
Since surgical procedures in the abdominal cavity of the body require insufflating gases to raise the cavity wall away from vital organs, the procedure is usually initiated by use of a Verres needle through which a gas is introduced into the body cavity. Thereafter, a trocar, which is a sharp pointed instrument, is inserted into a cannula assembly and used to puncture the peritoneum, i.e. the inner lining of the abdominal cavity wall. The gas provides a slight pressure which raises the wall surface of the peritoneum away from the vital organs thereby avoiding unnecessary contact with the organs by the instruments inserted into the cannula. This procedure also provides the surgeon with an adequate region in which to operate. Laparoscopic or endoscopic surgical instruments may then be inserted through the cannula to perform surgery within the abdominal cavity or other body portion. The cannula is also utilized for introducing tubes into the body as for drainage purposes or the like.
In view of the need to maintain the atmospheric integrity of the inner area of the cavity, a valve assembly which permits introduction of a trocar or any surgical instrument and which permits selective communication of the inner atmosphere of the cavity with the outside atmosphere is desirable. In this regard, there have been a number of attempts in the prior art to provide such atmospheric integrity.
One form of cannula assembly includes a valve assembly which includes a flapper valve which is pivotally mounted within the valve assembly and is automatically opened by the trocar or other object when it is inserted into the proximal end of the valve assembly. See, e.g., U.S. Pat. No. 4,943,280 to Lander.
U.S. Pat. No. 4,960,412 relates to a catheter introducing system which includes a valve assembly having dual flexible resilient gaskets which permit introduction of a catheter by providing dual openings which are dimensioned to contact a catheter tube introduced into the unit. Introduction of the tube is accomplished by introducing the tube into the openings of the gaskets. A first valve prevents or minimizes the flow of blood from the valve assembly unit when the catheter tube is absent and the second valve prevents or minimizes the flow of blood from the valve assembly when the catheter tube is present.
Another valve includes finger operated levers for controlling an inner valve formed of a plurality of radially movable members which join in adjacent relation to close the valve opening and which separate to permit entry of an element into the valve opening. The members are concentrically positioned and arranged to block the opening when the levers are at rest and to open in a manner to form a substantially circular passage-way when the levers are squeezed toward each other against the bias of a spring positioned therebetween.
Although attempts have been somewhat successful in providing a valve assembly which maintains the integrity of the atmospheric interface between the inlet of the valve assembly and the atmosphere outside the valve assembly, none have provided the degree of control to the user whereby opening adapted to facilitate the introduction of an instrument into the human body can be controlled selectively, opened or closed, in sequence and in a manner which positively retains the desired interface between the two atmospheres as may be required by the operator. The present invention provides a valve assembly which may be incorporated into a cannula assembly or utilized in combination with any type of tubular member for introduction into the body of a patient while permitting introduction of instruments into the body. At all times, the surgeon maintains control over the interface between the atmospheres within and without the patient's body. Moreover, the present invention makes it possible to introduce instruments of varying sizes into the body and insures the maintenance of a gas seal despite instrument manipulation therethrough.